The rapper reportedly spilled the beans during a concert in Atlantic City, N.J. Sunday night, whenhe paused during his set to ask the crowd to "stop the music and make noise for my baby mama," referring to Kardashian, who was in the audience.

On Monday, Kim posted a note titled "New Year, New Beginnings" on her website confirming the news. "It’s true!! Kanye and I are expecting a baby," she wrote. We feel so blessed and lucky and wish that in addition to both of our families, his mom and my dad could be here to celebrate this special time with us. Looking forward to great new beginnings in 2013 and to starting a family. Happy New Year!!! Xo"

The Kardashian family seems overjoyed at the news. Kim's sister, X Factor host Khloe Kardahian Odom, tweeted: "KIMYE!" followed by, "Keeping secrets is hard with so many family members! Especially when you are so freaking excited! Love is everything!"

And their other sister, Kourtney, tweeted: "Been wanting to shout from the rooftops with joy and now I can! Another angel to welcome to our family."